Method of fabricating light emitting device

ABSTRACT

A method of fabricating a light emitting device includes forming a plurality of light emitting elements on light emitting element mounting regions, respectively, of a substrate, forming lens supports on the light emitting element mounting regions, respectively, are raised relative to isolation regions of the substrate located between neighboring ones of the light emitting element mounting regions, and forming lenses covering the light emitting elements on the lens support patterns, respectively.

PRIORITY STATEMENT

This application is based on and claims priority from Korean PatentApplication No. 10-2009-0010236, filed on Feb. 9, 2009 in the KoreanIntellectual Property Office.

BACKGROUND

1. Field of the Inventive Concept

The present inventive concept relates to a method of fabricating a lightemitting device having an array of light emitting elements such as lightemitting diodes (LEDs).

2. Description of the Prior Art

A light emitting element such as a light emitting diode (LED) emitslight through electron-hole combination. The light emitting element haslow power consumption, a long lifespan, and strong anti-vibrationcharacteristics. Also, the light emitting element can be installed in anarrow space.

Light emitting elements are classified into vertical type of lightemitting elements, lateral type of light emitting elements, flip chiptype of light emitting elements, and the like.

The light emitting elements, after being fabricated as individualcomponents, are packaged to form a light emitting device. Morespecifically, the light emitting device includes a sub-mount onto whichlight emitting elements are mounted, a slug having reflectivity, leadsconnecting the light emitting elements to a circuit of a flexibleprinted circuit board, wires electrically connecting the leads to thelight emitting elements, a plastic package body protecting theabove-described components, a flexible printed circuit board attached toa bottom part of the package body, and a heat dissipation board fordissipating heat generated by the flexible printed circuit board.

The light emitting device transfers heat through the plastic packagebody. Therefore, the heat is not effectively dissipated and thus thelight emitting characteristics of the device may deteriorate over time.Also, the light emitting device is made up of several separatecomponents, including the package body. Therefore, it can be difficultto miniaturize the light emitting device.

Recently, the mounting of light emitting device to a substrate has beenconsidered as a way to increase the dissipation of heat generated by thedevice. However, in the case in which light emitting elements aremounted to a substrate, it can be difficult to efficiently condense thelight emitted from the respective light emitting elements.

SUMMARY

According to one aspect of the present inventive concept, there isprovided a method of fabricating a light emitting device, which includesmounting light emitting elements to a substrate at light emittingelement mounting regions of the substrate, respectively, forming apattern of lens supports on the light emitting element mounting regions,respectively, and forming lenses on the lens supports over the lightemitting elements, respectively. The light element mounting regions ofthe substrate are separated from one another by isolation regions of thesubstrate. Thus, each of the lens supports is raised relative to theisolation regions so as to have a step height with respect to theisolation regions.

According to another aspect of the present inventive concept, there isprovided a method of fabricating a light emitting device, which includesforming a plurality of zener diodes in a surface of an undoped substrateat light emitting element mounting regions of the substrate,respectively, mounting light emitting elements on the light emittingelement mounting regions of the substrate, respectively, forming apattern of lens supports on the light emitting element mounting regions,respectively, and forming lenses on the lens supports over the lightemitting elements by dispensing droplets of lens forming material onupper surfaces of the lens supports. The light emitting elements aremounted to the light mounting regions at a surface of the substrateopposite the surface in which the zener diodes are formed. Also, thelight emitting mounting regions of the substrate are separated from oneanother by isolation regions of the substrate. Thus, each of the lenssupports is raised relative to the isolation regions so as to have astep height with respect to the isolation regions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventive concept will be better understood from thefollowing detailed description of preferred embodiments thereof taken inconjunction with the accompanying drawings, in which:

FIG. 1A is a perspective view of a light emitting device;

FIG. 1B is a perspective view of the bottom of the light emittingdevice;

FIG. 2 is a sectional view of the light emitting device taken along lineA-A′ of FIG. 1A;

FIGS. 3 to 11 are sectional views illustrating a first embodiment of amethod of fabricating the light emitting device, shown in FIGS. 1A, 1Band 2, according to the present inventive concept;

FIGS. 12A to 12C are schematic diagrams of a lens support pattern andlens of the light emitting device;

FIG. 13 is a perspective view of another example of a light emittingdevice fabricated by the first embodiment of the method according to thepresent inventive concept;

FIG. 14 is a perspective view illustrating still another example of alight emitting device fabricated by the first embodiment of the methodaccording to the present inventive concept;

FIGS. 15 and 16 are sectional views illustrating a second embodiment ofa method of fabricating a light emitting device according to the presentinventive concept;

FIGS. 17 and 18 are sectional views illustrating a third embodiment of amethod of fabricating a light emitting device according to the presentinventive concept;

FIGS. 19 to 22 are sectional views illustrating a technique in a methodof fabricating a light emitting device according to the presentinventive concept;

FIG. 23 is a sectional view illustrating another technique in a methodof fabricating a light emitting device according to the presentinventive concept;

FIGS. 24 and 25 are sectional views illustrating still another techniquein a method of fabricating a light emitting device according to thepresent inventive concept;

FIG. 26 is a perspective view of another light emitting device;

FIG. 27 is a sectional view of the light emitting device, taken alongline B-B′ of FIG. 26; and

FIGS. 28 to 31 are sectional views illustrating an embodiment of amethod of fabricating the light emitting device, shown in FIGS. 26 and27, according to the present inventive concept.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present inventive concept will be describedin detail hereinafter with reference to the accompanying drawings. Likereference numerals are used to designate like elements throughout thedrawings. Also, in the drawings, the sizes and relative sizes ofelements and layers, etc. may be exaggerated for clarity.

A first embodiment of a method of fabricating a light emitting deviceaccording to the present inventive concept will now be described indetail with reference to FIGS. 1A to 11.

First, referring to FIGS. 1A, 1B, 2, and 3, zener diodes 20 are embeddedin a substrate 10. The substrate 10 may be a sapphire substrate, asilicon substrate, a silicon carbide (SiC) substrate, a sapphiresubstrate having gallium nitride formed on an upper part thereof, asilicon substrate having gallium nitride formed on an upper partthereof, or a silicon carbide substrate having gallium nitride formed onan upper part thereof.

First conductivity type semiconductor regions 21 are formed by dopingthe substrate 10 at a lower surface thereof with first impurities. Thedoping can be carried out by ion implantation, thermal diffusion, orplasma doping. The first type impurities may be P-type impurities.

Second conductivity type semiconductor regions 22 are formed by dopingthe substrate 10, adjacent the first conductivity type semiconductorregions 21, with second impurities having an opposite conductivity tothe first impurities such that the second conductivity typesemiconductor regions 22 contact the first conductivity typesemiconductor regions 21. Again, the doping can be carried out by ionimplantation, thermal diffusion, or plasma doping. The second impuritiesmay be N-type impurities.

Preferably, the substrate 10 is doped such that first impurities have arelatively low density in the first conductivity type semiconductorregions 21, and such that the second impurities have a relatively highdensity in the second conductivity type semiconductor regions 22. Forexample, the doping is carried out such that the density of the firstimpurities is greater than 5×10¹⁶/cm³ and less than 1×10¹⁸/cm³, and thedensity of the second impurities is higher than that of the firstimpurities.

The first conductivity type semiconductor regions 21 and the secondconductivity type semiconductor regions 22 form PN junctions, andconstitute zener diodes 20.

Referring to FIGS. 1A, 2, and 4, a protection pattern 900 is then formedon the lower surface of the substrate 10, and a protection layer 910 isformed on the upper surface of the substrate 10. More specifically,protection layers are formed on the lower and upper surfaces of thesubstrate 10, respectively. Then, a first photoresist pattern 1000 isformed over the protection layer formed on the lower surface of thesubstrate 10. Then the protection layer formed on the lower surface isetched using the first photoresist pattern 1000 as an etching mask toform the protection pattern 900. At this time, the first photoresistpattern 1000 and the protection pattern 900 expose regions of the deviceat boundaries between light emitting element mounting regions I andisolation regions II (described later on in more detail). The protectionpattern 900 and the protection layer 910 may be formed of siliconnitride or silicon oxide.

Referring to FIGS. 1A, 1B, 2, 4, and 5, the substrate 10 is then etchedusing the protection pattern 900 as an etching mask. In this respect,the substrate 10 may be anisotropically wet etched. In this case, thewet etching is performed using a wet etching solution such as a KOHsolution. The first photoresist pattern 1000 is dissolved by the KOHsolution. Also, at this time, the protection layer 910 prevents theupper surface of the substrate 10 from being damaged by the KOHsolution. Accordingly, as illustrated in FIG. 5, pyramidal grooves 35,each having a cross-sectional area that gradually decreases from onesurface of the substrate 10 towards the other, are formed in thesubstrate 10. As is also illustrated in FIG. 5, each groove 35 may havea V-shaped the profile. As a result, at least one groove 35 is formed atthe border between neighboring light emitting element mounting regionsI. In this embodiment of the present inventive concept, two grooves 35are formed at the border between neighboring light emitting elementmounting regions I. However, the inventive concept is not limited to anyparticular of number of grooves being formed at the border betweenneighboring light emitting element mounting regions.

The substrate 10 is exposed to the wet etching solution until a hole 30,constituting an opening in the upper surface of the substrate 10, isformed at the end of each groove 35. As described above, the protectionlayer 910 is formed on the upper surface of the substrate 10. Therefore,the etching of the substrate to form the grooves 35 may be stopped bythe protection layer 910.

After the grooves 35 and the through-holes 30 are formed, any remnantsof protection pattern 900 and protection layer 910 are removed by, forexample, buffered oxide etchant (BOE) or hydrofluoric acid (HF).Referring to FIG. 6, a protection layer 40 comprising an oxide is thenformed on the exposed substrate 10, by for example, a thermal oxidationmethod.

Referring to FIG. 7, a set 55 of rear electrodes is then formed on thelower surface of the substrate 10, and a set of front electrodes 50 isformed on the upper surface of the substrate 10. The forming of thefront electrode set 50 and the rear electrode set 55 may be performedsequentially in any order.

In order to form the front electrode set 50, a conductive layer isformed on the upper surface side of the substrate 10 using, for example,a sputtering method or an electroplating method. The conductive layer ispreferably formed of at least one material, having a superiorconductivity and adhesion with respect to the protection layer 40,selected from the group consisting of Ti, Pt, Au, Cr, Ni, Cu, and Ag.The conductive layer is then patterned to form a first front electrode50 a and a second front electrode 50 b spaced apart from each other.

The rear electrode set 55 may be formed using the same material andprocess as the front electrode set 50. Thus, the rear electrode 55 setmay be made up of first and second rear electrodes 55 a and 55 b. Therear electrode set 55 contacts the front electrode set 50 through thethrough-holes 30. Specifically, each first rear electrode 55 a maycontact a respective first front electrode 50 a, and each second rearelectrode 55 b may contact a respective second front electrode 50 b.Furthermore, each first rear electrode 55 a and second rear electrode 55b overlap a first type semiconductor region 21 of a zener diode 20.Similarly, the first and second rear electrodes 55 b overlap the secondtype semiconductor region 22 of the zener diode 100.

Referring to FIG. 8, light emitting elements 100 are mounted to thefront electrode set 50 at the upper surface of the substrate 10, i.e.,opposite the surface in which the zener diodes 20 are formed. Each lightemitting element 100 may be a blue light emitting element that generatesblue light. In the case in which an excessive voltage is applied to alight emitting element 100 due to static electricity, the zener diode 20associated therewith forms a bypass for the current to prevent the lightemitting element 100 from being damaged.

Each light emitting element is a component that produces light when avoltage is applied thereto (through the front electrodes 50 a and 50 b),i.e., is an individual light source. To this end, each light emittingelement 100 includes a light emitting element support substrate 110, anda first conduction type first conductive pattern 111, a light emittingpattern 112, and a second conduction type second conductive pattern 113,which are laminated in the foregoing sequence on the light emittingelement support substrate 110. These layers will now be described inmore detail.

The first conductive pattern 111 may be of a first conduction type(e.g., n-type), and the second conductive pattern 113 is of a second(i.e., the opposite) conduction type (e.g., p-type).

The light emitting pattern 112 corresponds to a region in which carriers(e.g., electrons) of the first conductive pattern 111 and carriers(e.g., holes) of the second conductive pattern 113 combine to generatelight. In this respect, the light emitting pattern 112 may be formed ofa well layer and a barrier layer. In this case. Carriers (i.e.,electrons and holes) accumulate and combine in the well layer becausethe well layer has a band gap that is smaller than that of the barrierlayer. The light emitting pattern 112 may have a signal quantum well(SQW) structure or a multiple quantum well (MQW) structure. A SQWstructure would have only one well layer, and an MQW structure wouldinclude multiple well layers. Furthermore, at least one of the welllayer and the barrier layer may be doped with at least one of B, P, Si,Mg, Zn, Se, and Al to establish a desired or particular light emittingcharacteristic of the light emitting element 100.

Although not illustrated in the drawing, a first electrode may be formedon the first conductive pattern 111. The first electrode may be made ofa transparent or opaque metal. The first electrode may include at leastone of indium thin oxide (ITO), copper (CU), nickel (Ni), chrome (Cr),gold (Au), titanium (Ti), platinum (Pt), aluminum (Al), vanadium (V),tungsten (W), molybdenum (Mo), and silver (Ag).

A second electrode (not illustrated) may be formed on the secondconductive pattern 113. The second electrode may be made of a materialhaving a high reflectivity. For example, the second electrode may bemade of at least one of silver (Ag) and aluminum (Al).

The light emitting element 100 may be mounted on the front electrode set50 in a flip-chip manner. In this respect, the light emitting element100 may be mounted using solder 121 and 123. For example, AgSn, PbSn, orAuSn is used as the solder 121 and 123. The solder 121 connects thefirst conductive pattern 111 to the second front electrode 50 b, and thesolder 123 connects the second conductive pattern 113 to the first frontelectrode 50 a. However, it should be noted that the first conductivepattern 111 and the second conductive pattern 113 may be connected toeither of the first and second front electrodes 50 and 50 b,respectively, for each light emitting element 100.

Referring to FIGS. 1A to 9, an insulating layer 200 is then formed onthe substrate 10 over the light emitting elements 100 and the frontelectrode set 50. The insulating layer 200 may be formed using a spincoating method, a drop method, or a spray coating method. The insulatinglayer 200 may be a layer of silicon resin, and serves to protect thelight emitting elements 100. Also, the insulating layer 200 ispreferably formed to a thickness of 100 to 300 μm.

The insulating layer 200 may also include phosphors 150. The phosphors150 may be mixed with silicon resin that forms the body of theinsulating layer 200, and may be spread on the substrate 10 using a spincoating method, drop method, or spray coating method.

In this embodiment of the present inventive concept, the insulatinglayer 200 is formed by depositing phosphors 150 on the substrate 10, andsubsequently forming and curing a layer of silicon resin on thesubstrate 10. Accordingly, the phosphors 150 cover the upper and sidesurfaces of the light emitting elements 100 and the upper surface of thesubstrate 10, and thus the light emitted from the light emitting element100 radiates into the air via the phosphors 150.

The phosphors 150 may include those which generate red light, yellowlight, and green light. To this end, the following phosphors may beused.

The phosphors 150 may be selected from the group consisting ofnitride/oxynitride-based phosphors mainly vitalized by lanthanoidelements such as Eu, Ce, and the like, alkaline-earth halogen apatitephosphors mainly vitalized by lanthanoid elements such as Eu andtransition metallic elements such as Mn, alkaline-earth metal boric acidhalogen phosphors, alkaline-earth metal aluminate phosphors, rare-earthaluminate mainly vitalized by lanthanoid elements such as alkaline-earthsilicate, alkaline-earth emulsion, alkaline-earth thiogallate,alkaline-earth silicon nitride, germanate, and Ce, and organic andorganic complexes mainly vitalized by lanthanoid elements such asrare-earth silicate and Eu.

The nitride-based phosphors mainly vitalized by lanthanoid elements suchas Eu, Ce, and the like, may be M₂Si₅N₈:Eu (wherein M is at least one ofSr, Ca, Ba, Mg, and Zn). The nitride-based phosphors may additionallyinclude MSi₇N₁₀:Eu, M₁₈Si₅O_(0.2)N₈:Eu, M_(0.9)Si₇O_(0.1)N₁₀:Eu (whereinM is at least one of Sr, Ca, Ba, Mg, and Zn).

The oxynitride-based phosphors mainly vitalized by lanthanoid elementssuch as Eu, Ce, and the like, may be MSi₂O₂N₂:Eu (wherein M is at leastone of Sr, Ca, Ba, Mg, and Zn).

The alkaline-earth halogen apatite phosphors mainly vitalized bylanthanoid elements such as Eu and transition metallic elements such asMn may be M₅(PO₄)₃X:R (wherein M is at least one of Sr, Ca, Ba, Mg, andZn, X is at least one of F, Cl, Br, and I, and R is at least one of Eu,Mn, and Eu).

The alkaline-earth metal boric acid halogen phosphors may be M₂B₅O₉Z:R(wherein M is at least one of Sr, Ca, Ba, Mg, and Zn, X is at least oneof F, Cl, Br, and I, and R is at least one of Eu, Mn, and Eu).

The alkaline-earth metal aluminate phosphors may be SrAl₂O₄:R,Sr₄Al₁₄O₂₅:R, CaAl₂O₄:R, BaMg₂Al₁₆O₂₇ :R, BaMg₂Al₁₆O₁₂:R, andBaMgAl₁₀O₂₇:R (wherein R is Eu, Mn, or Eu).

The rare-earth emulsion phosphors may be La₂O₂S:Eu, Y₂O₂S:Eu, Gd₂O₂S:Eu,and the like.

The rare-earth aluminate phosphors mainly vitalized by lanthanoidelements such as Ce may be Y₃Al₅O₁₂:Ce, (Y_(0.8)Gd_(0.2))₃Al₅O₁₂:Ce,Y₃(Al_(0.8)Ga_(0.2))₅O₁₂:Ce, yttrium aluminum garnet (YAG) phosphorsrepresented in a composition equation of (Y,Gd)₃(Al,Ga)₅O₁₂, and thelike. Also, the rare-earth aluminate phosphors may be Tb₃Al₅O₁₂:Ce,Lu₃Al₅O₁₂:Ce, and the like, in which a part or the entire part of Y hasbeen replaced by Tb, Lu, and the like.

The alkaline-earth silicate phosphors may be formed of silicate, andrepresentative phosphors of (SrBa)₂SiO₄:Eu and the like.

Other phosphors may be SnS:Eu, Zn₂GeO₄:Mn, MGa₂S₄:Eu, and the like(wherein M is at least one of Sr, Ca, Ba, Mg, and Zn, and Xis at leastone of F, Cl, Br, and I).

The above-described phosphors may also contain Tb, Cu, Ag, Au, Cr, Nd,Dy, Co, Ni, and Ti, substituted for or in addition to Eu.

Referring now to FIGS. 1A, 9, and 10, a second photoresist pattern 1100is formed on the insulating layer 200. In this embodiment of theinventive concept, the second photoresist pattern 1100 is formed so asto have discrete circular segments each centered over (verticallyaligned with) a respective light emitting element 100.

Then, the insulating layer 200 is etched using the second photoresistpattern 110 as an etching mask. The etching may be carried out by a dryetching process. Accordingly, the insulating layer 200 is etched in avertical direction, i.e., a direction perpendicular to the upper andlower surfaces of the substrate 10. As a result, that portion of theinsulating layer 200 disposed on the isolation regions II is removed,and the remaining portion of the insulating layer 200 forms a pattern oflight supports 300, as illustrated in FIG. 11.

Thus, the pattern of lens supports 300 has a step height relative to theupper surface of the substrate 100. Also, in this case, and as bestshown in FIG. 1A, the lens supports 300 are cylindrical in accordancewith the shape of the second photoresist pattern 1100, each cylindricallens support 300 covering a light emitting element 100.

Referring to FIGS. 1A, 2, and 12A to 12C, a lens 400 is then formed oneach lens support 300. The lenses 400 serve to condense light emittedfrom the light emitting elements 100.

An inkjet printing method may be used to form the lenses 400.Specifically, the lens forming process may be performed using a microinkjet method to cover at least part of the upper surface of each lenssupport 300 with a droplet of, for example, silicon resin. Then, thedroplet is cured to strengthen the resultant lens 400. Also, dependingon the step height of the pattern of lens supports 300, the lenses 400may be formed so as to cover part of the side surface of the pattern oflens supports 300 and the isolation region II.

In this embodiment of the present inventive concept, each lens 400 isformed so as to be hemispherical due to the surface tension provided atthe edge of the upper surface of the lens support 300. That is, theupper surface of each lens support 300 is circular. Accordingly, thebottom surface of the lens 400 will be circular, and the lens will havethe shape of a segment of a sphere.

In this respect, FIGS. 12A to 12C show that as the width w1, w2, or w3of the lens support pattern 300 increases, the radius of curvature ofthe lens 400 becomes larger for lenses of the same volume.

Specifically, as illustrated in FIG. 12A, if the lens support 300 isnarrow, the lens 400 has a relatively great height Hl. In this case, thelens 400 provides a high degree of directionality to the light emittedby the light emitting device 100 covered by the lens 400. As illustratedin FIGS. 12B and 12C, the wider (w2, w3) the lens support pattern 300is, the greater is the surface tension between the lens support 300 andthe droplet (of silicon resin) used to form the lens (assuming that thedroplets all have the same volume), and the smaller the droplet becomesin terms of its height (H2, H3). As illustrated in FIG. 12C, the lens400 having a large radius of curvature provides the greatest degree ofuniformity in dispersing the light emitted by the light emitting element100 covered by the lens.

Accordingly, the above-described method facilitates the forming oflenses 400 optimized with respect to providing any one of severaldifferent effects. Such optimized lenses 400 can be produced simply byforming lens supports 300 to specific predetermined dimensions (widths),and dispensing droplets of predetermined volumes of transparent (lens)material onto the lens supports 300.

Referring again to FIGS. 1A and 2, the lenses 400 are preferably made ofa material whose index of refraction is lower than or equal to that ofthe pattern of lens supports 300. Accordingly, the light emitted from alight emitting element 100 sequentially passes through a lens support300 and a lens 400, and into the air. In this case, the indices ofrefraction of the lens support 300, the lens 400, and the air decreasein the foregoing order. Therefore, the phenomenon of internal reflectionis minimized and thus, the optical emission efficiency is maximized.

As is clear from the description above, the method according to theinventive concept facilitates the forming of various arrangements lightemitting elements on a substrate. For example, according to theinventive concept, light emitting elements may be formed in a one- ortwo-dimensional array, i.e., in a periodic arrangement. Also, the lightemitting elements 100 of the light emitting device can each emit red,green, or blue light. Also, the lenses 400 and the insulating layer 200are formed by discrete processes in the manner described above.Therefore, the lenses 400 are less likely to be damaged compared to acase in which a pre-fabricated sheet of lenses on an insulating layer isattached to a substrate 10.

FIG. 13 shows another light emitting device fabricated according to thepresent inventive concept. This light emitting device is fabricated asfollows.

Light emitting devices are formed on a substrate 10 using processesdescribed above with reference to FIGS. 3 to 11.

In this case, though, the upper surface of each segment of thephotoresist pattern 1100 (FIG. 10) has the shape of a quadrangle.Accordingly, as illustrated in FIG. 13, each lens support 300′ is formedas a parallelepiped (a pillar with quadrangular sides), and each lens400′ is formed in the shape of a pyramid having a quadrangular base,curved sides and curvilinear edges.

FIG. 14 shows another light emitting device fabricated according to thepresent inventive concept. This light emitting device is fabricated asfollows.

Light emitting devices are formed on a substrate 10 using processes asdescribed above with reference to FIGS. 3 to 11.

In this case, though, the upper surface of each segment of thephotoresist pattern 1100 (FIG. 10) has the shape of a triangle.Accordingly, as illustrated in FIG. 14, each lens support 300″ is formedas a triangular pillar, and each lens 400″ is formed in the shape of apyramid having a triangular base, curved sides and curvilinear edges.

Although a first embodiment of a method of fabricating a light emittingdevice according to the inventive concept has been described above withrespect to the forming of specifically shaped lens supports and lenses,the inventive concept is not so limited. That is, is should be clearthat the inventive concept can be practiced to fabricate a lightemitting device whose lens supports and lenses have shapes other thanthose specifically described above.

Next, a second embodiment of the present inventive concept will bedescribed in detail with reference to FIGS. 3 to 7, 9 to 11, 15 and 16.

First, the sets of front rear electrodes 50 and 55 are formed usingprocesses as described above with reference to FIGS. 3 to 7.

Referring to FIG. 15, light emitting elements 101 are then electricallyconnected to the front electrode set 50. In this embodiment of thepresent inventive concept, each light emitting element 101 includes alaminate of a first conduction type first conductive pattern 114, alight emitting pattern 115, and a second conduction type secondconductive pattern 116. The first conductive pattern 114 is directlyconnected to a front electrode 50 a, and the second conductive pattern116 is connected to a second front electrode 50 b by a wire 126. Then,the light emitting device having lens supports 300 and lenses 400, asillustrated in FIG. 16, is completed using processes as described abovewith reference to FIGS. 8 to 11. In this regard, the second embodimentcan be used to form lens supports and lenses of any of the other shapesdescribed above.

Next, a third embodiment of a method of fabricating a light emittingdevice according to the present inventive concept will be described indetail with reference to FIGS. 3 to 7, 9 to 11, 17, and 18.

First, the sets of front rear electrodes 50 and 55 are formed usingprocesses as described above with reference to FIGS. 3 to 7.

Referring to FIG. 17, light emitting elements 102 are then electricallyconnected to the front electrode set 50. In this embodiment of thepresent inventive concept, the light emitting element 102 includes alaminate of a first conduction type first conductive pattern 117, alight emitting pattern 118, and a second conduction type secondconductive pattern 119. The first conductive pattern 117 is connected tothe second front electrode 50 b by a first wire 127, and the secondconductive pattern 119 is connected to the first front electrode 50 a bya second wire 129. Then, the light emitting device having lens supports300 and lenses 400, as illustrated in FIG. 18, is completed usingprocesses as described above with reference to FIGS. 8 to 11. In thisregard, the third embodiment can be used to form lens supports andlenses of any of the other shapes described above.

Next, a method of fabricating a light emitting device, using onetechnique, according to the present inventive concept will be describedin detail with reference to FIGS. 3 to 8, and 19 to 22.

First, the sets of front rear electrodes 50 and 55 are formed usingprocesses as described above with reference to FIGS. 3 to 7. Then, lightemitting elements 100 are mounted on the substrate 10 as described abovewith respect to FIG. 8.

Referring to FIG. 19, an insulating layer 200 is then formed on thesubstrate 10 over the light emitting elements 100 and the frontelectrode set 50. In this case, phosphors 153 are dispersed throughoutthe insulating layer 200. In this embodiment, silicon resin in which thephosphors 153 have been dispersed is spread on the substrate 10, and theresulting layer is cured to form the insulating layer 200. Accordingly,the phosphors 153 are dispersed substantially uniformly throughout theentire thickness of the insulating layer 200.

Referring to FIG. 20, a second photoresist pattern 1100 is then formed,and the insulating layer 200 is dry etched using the second photoresistpattern 1100 as an etching mask.

As a result, as illustrated in FIG. 21, a pattern of lens supports 300is formed over the light emitting elements 100, and each lens support300 has phosphors 153 dispersed substantially uniformly therethroughout. Therefore, phosphors 153 surround each light emittingelement 100.

Referring to FIG. 22, lenses 400 are then formed on the lens supports300, in the manner described above, to complete to the light emittingdevice.

A method of fabricating a light emitting device, using anothertechnique, according to the present inventive concept, will be describedin detail with reference to FIGS. 3 to 12, and 23.

First, the front and rear electrode sets 50 and 55 are formed usingprocesses as described above with reference to FIGS. 3 to 8. Then, lightemitting elements 100 are mounted on the substrate 10 to the frontelectrode set 50. Referring to FIG. 23, phosphors 150 are spread ontothe substrate 10. In this case, the phosphors 150 may be dissolved in avolatile material, e.g. acetone, so that they may be easily spreadacross the substrate 10. Subsequently, the acetone is volatilized, e.g.,by being heated, and is thereby removed. Accordingly, the phosphors 150remain on the upper surface of the substrate 10 and the upper and sidesurfaces of the light emitting elements 100. Thus, the light emittedfrom each light emitting element 100 radiates into the air via phosphors150.

Then, as was shown in FIG. 9, an insulating layer 200 is formed on thephosphors 150. As a result, phosphors 150 occupy only a lower part ofthe insulating layer 200.

Then, the light emitting device is completed using processes asdescribed above with reference to FIGS. 10 to 12.

A method of fabricating a light emitting device, using yet anothertechnique, according to the present inventive concept will be describedin detail with reference to FIGS. 3 to 8, 10 to 12, 24, and 25.

First, front and rear electrode sets 50 and 55 are formed on a substrate10 using processes as described above with reference to FIGS. 3 to 8.Then, light emitting elements 100 are mounted on the front electrode set50.

Referring to FIG. 24, an insulating layer 200 is then formed on thesubstrate 10 over the light emitting elements 100 and the frontelectrode set 50.

Then, phosphors 154 are spread on the insulating layer 200. In thisrespect, the phosphors 154 may be applied to the insulating layer 200 inthe same way as described above with reference to FIG. 23.

Then, light emitting device as illustrated in FIG. 25 is completed usingprocesses as described above with reference to FIGS. 10 to 12. Thus, inthis embodiment of the present inventive concept, the phosphors 154 areformed between the lenses 400 and the lens supports 300.

Next, another embodiment of a method of fabricating a light emittingdevice according to the present inventive concept will be described indetail with reference to FIGS. 3 to 8, 12, and 26 to 31.

First, front and rear electrode sets 50 and 55 are formed on a substrate10 using processes as described above with reference to FIGS. 3 to 8.Then, light emitting elements 100 are mounted on the front electrode set50.

Referring to FIGS. 26 to 28, an insulating layer 203 is then formed onthe substrate 10 over the light emitting elements 100 and the frontelectrode set 50.

In this embodiment of the present inventive concept, the insulatinglayer 203 is formed of multiple films of material. Specifically, a firstinsulating film 210 and a second insulating film 220 are sequentiallyformed on the substrate 10 to constitute the insulating layer 203. Thefirst insulating film 210 is preferably of a material having an index ofrefraction that is higher than or equal to that of the second insulatingfilm 220.

Referring to FIGS. 26 to 29, a second photoresist pattern 1100 is thenformed on the second insulating film 220. The second photoresist pattern110 is made up of discrete segments of photoresist which are verticallyaligned with the light-emitting elements, respectively.

Then, the second insulating layer 220 is etched using the secondphotoresist pattern 1100 as an etching mask, thereby patterning thesecond insulating film 220. As a result, discrete segments of the secondinsulating film 220 are left over portions of the first insulating film210 and the underlying light emitting elements 100, respectively, andthe remainder of the first insulating film 210 is exposed.

Referring to FIG. 30, a third photoresist pattern 1200 is then formed onthe substrate 10 over the insulating layer. The third photoresistpattern 1200 has essentially the same pattern and alignment with thesubstrate 10 as the second photoresist pattern 1100. However, thediscrete segments of the third photoresist pattern 1200 are wider thanthose of the second photoresist pattern 1100. Then, the first insulatingfilm 210 is etched using the third photoresist pattern 1200 as anetching mask. Accordingly, as illustrated in FIG. 31, a pattern of lenssupports 303 is formed in which each of the lens supports 303 has afirst (lower) lens support portion 310 and a second (upper) lens supportportion 320. Also, the pattern of lens supports 303 is formed such thata step is formed between the first lens support portion 310 and thesecond lens support portion 320 of each lens support 303.

Then lenses 403, as shown in FIGS. 26 and 27, are formed on the lenssupports 303, respectively, using an inkjet method as described abovewith reference to FIG. 12. In this respect, each of the lenses 403 maybe formed to cover the upper and side surfaces of a second lens supportportions 320. Also, each lens 403 may further cover a part of the sidesurface of a first lens support portion 310 and the upper surface of thesame first lens support portion 310.

In the light emitting device fabricated as described above according tothe inventive concept, the light emitted from each light emittingelement 100 sequentially passes through the first lens support pattern310, the second lens support pattern 320, and the lens 403, and theninto the air layer. The first lens support portions 310 are made ofmaterial having an index of refraction that is higher than or equal tothe index of refraction of the material of the second lens supportportions 320, and the index of refraction of the material of the secondlens support portions 320 is higher than or equal to the index ofrefraction of the lenses 403. Accordingly, the phenomenon of internalreflection of the light is minimized, and thus the optical emissionefficiency is optimized.

Finally, embodiments of the inventive concept have been described hereinin detail. The inventive concept may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments described above. Rather, these embodiments were described sothat this disclosure is thorough and complete, and fully conveys theinventive concept to those skilled in the art. Thus, the true spirit andscope of the inventive concept is not limited by the embodimentsdescribed above but by the following claims.

1. A method of fabricating a light emitting device, comprising: mountinglight emitting elements to a substrate at light emitting elementmounting regions, respectively, of the substrate, separated from oneanother by isolation regions of the substrate; forming a pattern of lenssupports on the light emitting element mounting regions, respectively,wherein each of the lens supports is raised relative to the isolationregions so as to have a step height with respect to the isolationregions; and forming, on the lens supports, lenses over the lightemitting elements, respectively, wherein the forming of the pattern oflens supports comprises forming, on the substrate, an insulating layerthat covers the light emitting elements, and removing part of theinsulating layer, wherein the forming of the insulating layer comprisessequentially forming a first insulating film and a second insulatingfilm on the substrate, and wherein the forming of the pattern of lenssupports comprises patterning the second insulating to form upperportions of the lens supports, and patterning the first insulating filmto form lower portions of the lens supports each disposed beneath andwider than a respective one of the upper portions of the lens supports,whereby each of the lens supports has a step therein.
 2. The method ofclaim 1, wherein the forming of the lenses comprises dispensing dropletsof lens forming material on upper surfaces of the lens supports.
 3. Themethod of claim 1, wherein the removing of part of the insulating layercomprises etching the insulating layer.
 4. The method of claim 1,wherein the insulating layer is a material having an index of refractionthat is higher than or equal to an index of refraction of the lenses. 5.The method of claim 1, further comprising providing phosphors betweenthe light emitting element and the lenses.
 6. The method of claim 1,wherein the substrate is an undoped substrate, and the method furthercomprises forming, in a surface of the substrate, zener diodes at thelight emitting element mounting regions of the substrate, respectively,and wherein the light emitting elements are mounted to the substrate atthe other surface of the substrate.